Apparatus and method for cooperatively transmitting downlink between base station and relay station

Abstract

The present invention relates to an apparatus and method for cooperatively transmitting a downlink between a base station and a relay station. According to one embodiment of the present invention, a method for cooperatively transmitting a downlink signal between a base station and a relay station in a wireless broadband communication system comprises the steps of: receiving cooperative transmission data from the base station and transmitting an acknowledgement message corresponding to the cooperative transmission data to the base station; receiving scheduling information for transmitting the cooperative transmission data by a cooperative transmission scheme; and transmitting the data cooperative transmission data to a terminal in reference to the scheduling information.

Description

TECHNICAL FIELD[0001]The present invention relates to a wireless communication system using a relay station, and more particularly, to an apparatus and method for cooperatively transmitting a downlink signal to a terminal by a base station and a relay station.BACKGROUND ART[0002]In the next generation wireless communications system, a relay station (RS) is being introduced so as to increase cell coverage and to enhance a data transmission rate.[0003]In the conventional wireless communications system using a relay station, there are not only wireless resources which consist of time or a frequency between a base station (BS) and a mobile station (MS), but also wireless resources between BS-RS, and wireless resources between RS-MS. Since a signal between BS-RS may be different from a signal between RS-MS, interference may occur when using the same wireless resources. This may lower the performance. In order to prevent this, has been considered a cooperative silencing technique in which...

AI Technical Summary

Benefits of technology

[0008]Therefore, an object of the present invention is to provide an apparatus and method for cooperatively transmitting a downlink between a base station and a relay station, by transmitting scheduling information to the relay station from the base station even if a transmission error has occurred in a link between the base station and the relay station.

[0023]In the present invention, the scheduling information may be transmitted to the relay station from the base station even if an error has occurred in a transmission link between the base station and the relay station. This may prevent waste of wireless resources allocated to be transmitted to the terminal. Furthermore, this may prevent degraded transmission efficiency to the terminal occurring from that the base station and the relay station do not perform an effective cooperative transmission. And, this may solve a problem such as time delay occurring when a signal is transmitted to the terminal.

Problems solved by technology

Since a signal between BS-RS may be different from a signal between RS-MS, interference may occur when using the same wireless resources.

This may lower the performance.

However, the cooperative silencing technique may have the following problems.

Firstly, since the BS is in an idle state using no wireless resources at a transmission section between the RS and the MS, a resource loss may occur.

However, in a substantial communication environment, the RS may not successfully receive cooperative transmission data transmitted from the BS.

[7] In spite of this problem, the conventional art has proposed no method for preventing a transmission error in a link between the BS and the RS.

Since there is no consideration about a transmission error in a link between the BS and the RS in the conventional art, when the RS has not successfully received data transmitted from the BS, wireless resources pre-allocated so as to be transmitted to the MS may be wasted.

Furthermore, since the BS and the RS do not perform an effective cooperative transmission, transmission efficiency to the MS may be lowered and long time delay may occur.

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